Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Polymer and Materials Science  (2)
  • Inorganic Chemistry  (1)
  • 1995-1999  (3)
Collection
Publisher
Years
Year
  • 1
    ISSN: 0887-6266
    Keywords: tensile drawing ; morphology ; polybutylene ; terephthalate ; Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The concept of the drawing of a molecular network has been employed to derive a total network draw ratio from the combination of the two deformations occurring in the production of poly(butylene terephthalate), PBT, fibers by the consecutive processes of melt spinning and cold drawing. The mechanical properties of PBT can then be more readily explained in terms of increases in this total network draw ratio. However, the preorientation and crystallization that occurs in the melt-spinning process can occur at different strain rates and temperatures, depending on the wind up speed employed, on the extensional viscosity of the polymer, and on the variation of the extensional viscosity with temperature. Therefore, for polymers such as poly(butylene terephthalate), which can exist in two crystalline forms, the morphology of the final drawn fiber might be expected to depend on the first melt-spinning stage of the process as well as on the total network draw ratio. In this work, density, birefringence, mechanical measurements, and WAXD measurements, which have been made on the melt-spun fibers and on the drawn fibers, are described. Small differences in some of the drawn yarn mechanical properties at the same overall network draw ratio are related to the crystallinity and in particular to differences in the proportion of the α and β phases present in the drawn yarn. These in turn are related to differences in the temperature and stress during melt spinning and drawing. © 1997 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 35: 2465-2481, 1997
    Additional Material: 18 Ill.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 2
    ISSN: 0323-7648
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Direct depth profiling techniques to date have largely lacked the necessary depth resolution to investigate interfacial phenomena of the order of the bulk correlation length (5 - 10 nm for a wide range of systems). Here we investigate the optimal spatial resolution and depth of probe that may be attained for composition  -  depth profiling of polymeric samples via nuclear reaction analysis (NRA) using the 2H(3He, 1H)4He reaction. We find that the spatial resolution can be greatly improved by using a grazing incidence geometry of the incident 3He beam on the sample, and analyzing the emitted protons in a backwards direction. This results in spatial resolutions down to about 3 nm at the sample surface, compared to a value of some 7 nm or more previously reported in earlier studies when emitted α-particles were detected in the forward direction. At the same time the depth to which samples can be profiled via the backwards emitted protons may be considerably extended relative to the α-particle detection mode, when the 3He beam impinges on the sample surface at normal incidence (up to about 4 μm into the sample for incident energies of 1.2 MeV in the proton-detection mode compared to only 1 μm for the equivalent α-particle detection mode).
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 3
    ISSN: 0044-2313
    Keywords: Arsenidostannates ; alkali - alkaline earth substitution ; [SnAs] nets isostructural grey arsenic ; crystal structure ; Zintl phases ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Arsenidostannates with [SnAs] Nets Isostructural to Grey Arsenic: Synthesis and Crystal Structure of Na[Sn2As2], Na0.3Ca0.7[Sn2As2], Na0.4Sr0.6[Sn2As2], Na0.6Ba0.4[Sn2As2], and K0.3Sr0.7[Sn2As2]The metallic lustrous compounds Na[Sn2As2], Na0.3Ca0.7[Sn2As2], Na0.4Sr0.6[Sn2As2], Na0.6Ba0.4[Sn2As2] and K0.3Sr0.7[Sn2As2] were prepared from melts of mixtures of the elements. The compounds crystallize in the trigonal system (space group R3m, No. 166, Z = 3) with lattice constants see in “Inhaltsübersicht”. The structures are isotypic to Sr[Sn2As2] containing puckered ∞2[SnAs] nets which are stacked with a sequence of six layers. The E(I)/E(II) atoms are located between each second ∞2[SnAs] layer in trigonal antiprismatic interstices formed by As atoms. In the resulting ∞2[Sn2As2] double layers the ∞2[SnAs] nets are stacked in such a way that additional Sn - Sn contacts arise.
    Notes: Die metallisch glänzenden Verbindungen Na[Sn2As2], Na0,3Ca0,7[Sn2As2], Na0,4Sr0,6[Sn2As2], Na0,6Ba0,4[Sn2As2] und K0,3Sr0,7[Sn2As2] wurden aus Schmelzreaktionen, ausgehend von Gemengen der Elemente erhalten. Die Verbindungen kristallisieren trigonal, Raumgruppe R3m (Nr. 166), Z = 3, mit den Gitterkonstanten (pm): TextNa[Sn2As2]a = 400,6(2)c = 2758,1(5)c/a = 6,885Na0,3Ca0,7[Sn2As2]a = 410,1(2)c = 2648,6(5)c/a = 6,458Na0,4Sr0,6[Sn2As2]a = 411,7(2)c = 2718,5(5)c/a = 6,603Na0,6Ba0,4[Sn2As2]a = 409,2(2)c = 2793,4(5)c/a = 6,826K0,3Sr0,7[Sn2As2]a = 417,6(2)c = 2714,6(5)c/a = 6,500 - In den im Sr[Sn2As2]-Typ kristallisierenden Verbindungen sind zum grauen Arsen isostrukturelle ∞1[SnAs]-Netze ausgebildet, die senkrecht zur c-Achse eine Sechserschichtfolge aufweisen. Jeder zweite ∞1[SnAs]-Schichtzwischenraum ist von E(I)/E(II)-Atomen in trigonal antiprismatischen Lücken aus As-Atomen belegt. In den resultierenden ∞2[Sn2As2]-Doppelschichtpaketen sind die benachbarten ∞2[SnAs]-Netze so zueinander orientiert, daß relativ kurze Sn - Sn-Kontake ausgebildet werden.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...